Skoolkit

* Added the `PLOT` macro (for setting, resetting or flipping a pixel in a frame already created by an image macro)
* Added the `--begin` option to `bin2tap.py` (for specifying the address at which to begin conversion)
* The `--end` option of `bin2tap.py` now applies to raw memory files as well as SNA, SZX and Z80 snapshots
* Added the `--data` option to `tapinfo.py` (for showing the entire contents of header and data blocks)
* Added support to the `--ctl` option of `sna2skool.py` and `snapinfo.py` for reading control files from a directory
* Added the `x` and `y` parameters to the frame specification of the `UDGARRAY*` macro (for specifying the coordinates at which to render a frame of an animated image)
* Added support for replacement fields in the `args` parameter of the `CALL` macro, in the integer parameters of the `CHR`, `D`, `INCLUDE`, `N`, `POKES`, `R` and `SPACE` macros, and in the integer parameters and cropping specification of the `FONT`, `SCR`, `UDG` and `UDGARRAY` macros
* Fixed the bug that causes ‘e+1’ to be interpreted as a floating point number when it appears in a BASIC program

* Added the `--call-graph` option to `snapinfo.py` (for generating a call graph in DOT format)
* Added the `--ctl` option to `snapinfo.py` (for specifying a control file to use when generating a call graph)
* Added the `--org` option to `snapinfo.py` along with the ability to read binary (raw memory) files
* Added support to `snapinfo.py` for reading configuration from *skoolkit.ini*
* Added the `--ini` and `--show-config` options to `snapinfo.py` (for setting the value of a configuration parameter and for showing all configuration parameter values)
* Added the `DEFINE` macro (for defining new skool macros)
* Added the `LET` macro (for defining variables that can be retrieved by other macros via replacement fields)
* Added the `FORMAT` macro (for performing a Python-style string formatting operation on an arbitrary piece of text)
* Added the `expand` directive (for specifying skool macros to be expanded during ASM writer or HTML writer initialisation)
* Added the `tindex` parameter to the `FONT`, `SCR`, `UDG` and `UDGARRAY` macros (for specifying a transparent colour to use other than the default)
* Added the `alpha` parameter to the `FONT`, `SCR`, `UDG` and `UDGARRAY` macros (for specifying the alpha value to use for the transparent colour)
* Added the `refs` directive (for managing the addresses of routines that jump to or call an entry point)
* Added support for replacement fields in the integer parameters of the `FOR` and `PEEK` macros
* Added the `--page` option to `snapinfo.py` (for specifying the page of a 128K snapshot to map to 49152-65535)