Osgb

- Found and fixed a bug the core ellipsoid projection routine that was causing
the unexpectedly inaccurate results in higher latitudes.

- Extensive performance improvements to OSTN02 data look up

- random_grid function now checks that the random grid position
it selects is well inside the OSTN02 boundary

- parse_grid function will now parse a grid square name. For example
"parse_grid('TA')" will return (500000,400000).

- Fixed various typos in Pod sections in all modules, and added more
explanations in Background.pod

- Re-organized, and much faster, OSTN02 data look up

- format_grid now supports ... { form => 'SS' } ... to get just the grid square.

- Updated examples with proper documentation and improved plotting of maps

- Minor change in t/08out_of_range.t and t/13edge.t tests to allow for Perl
with "long double" enabled. Corresponding updates to documentation.
This does not affect any function; I've simply made the tests more
robust. I should add that "long doubles" do not appear to benefit this
module at all. The results and accuracy that I get are the same with
"long doubles" but everything runs about 10% slower.

- Re-worked the handling of points near the boundary of the OSTN02 polygon,
to avoid a potential loop in rare cases. This is unlikely to affect any
transformations with real coordinates (unless you spend a lot of time in
boats about 10km offshore), but avoids some problems in my testing with
random grid points.

- Simplified OSTN02 data access. Removed the OSGM02 height part of the
data as this is no longer used. This makes the module somewhat smaller
and a little faster to load.

- Added user interface to approximate conversion routines for quick Helmert
transformations: "grid_to_ll_helmert" and "ll_to_grid_helmert"

- Fixed a small bug in "parse_grid", so that it allows '/' character in map
sheet names, and therefore works with sheet names like: 'B:110/OL44'

- Corrected structure of POD documentation in Maps.pm and Background.pm

- Simplified testing of random grid references to give more reliable
results. Added more tests based on OS transformations, and to prove
some edge conditions.

- Small bug fixes only

- Removed the 'r' switch from the single use of the 'tr' function. This accidentally
created a dependency on perl 5.14 which caused several CPAN testers to fail 2.10.

- Added 'use 5.008' to main modules: everything should now work on perl 5.8 or better.

- Added note about accuracy of OSTN02 in grid square HP (far north of Shetland) and changed
the random round-trip tests to avoid this square. For reasons I do not understand, the
accuracy of round trip conversion with this implementation of OSTN02 is within a few mm
for most of the country, but suddenly drops to an average of about 25m in grid square HP.

- Minor clean up of pod formatting in a couple of places

- Complete simplification and restructure of the entire module

- Geo::Coordinates::OSGB now provides only:

grid_to_ll
ll_to_grid

- WGS84 is assumed as the default ellipsoid shape
- OSTN02 data is automatically used where necessary providing much a simpler interface
- New Helmert transformation routines automatically used outside OSTN02 coverage

- New module Geo::Coordinates::OSGB::Grid provides routines to parse and format grid references
-- general purpose "format_grid" for all formatting
-- general purpose "parse_grid" for all parsing

- New module Geo::Coordinates::OSGB::Maps provides outlines, bounding boxes, and titles for OSGB maps

- The functions `shift_ll_into_WGS84` and `shift_ll_from_WGS84` are no longer provided (or needed).

- The functions formerly provided by OSTN02.pm are integrated into OSGB.pm, so the subroutines
`OSGB36_to_ETRS89` and `ETRS89_to_OSGB36` are no longer provided (or needed).

- The functions to parse and format grid references are moved to OSGB/Grid.pm.

- The functions to parse and format lat/lon are removed, because they are better provided by other modules.

For more details, see the section on "Upgrading" in Background.pod

- Improved and generalized handling of maps to allow for multiple series, insets, and irregular boundaries
- New generic functions "format_grid_map" and "parse_map_grid" to replace the Landranger-specific functions
- Complete insets and extensions to sheet boundaries for Landranger maps
- Complete sheet boundaries for old One Inch 7th series maps
- Complete sheet boundaries for Explorer series of 1:25000 maps
- Reorganized distribution:
-- example scripts are in examples/
-- map definitions are in maps/
- Minor improvements to precision