Lakshmi

Fixed
- 'Cannot retrieve ticker' errors.

Added
- Option in `lak list assets` that omits printing of the long name (the
'Asset' column) if short name is being printed.
- Three Options in `lak list whatifs` to print Asset short name, omit printing
of long name if short name is being printed, and approximate number of shares
that need to be bought or sold (corresponding to the dollar delta returned).
The last field is only printed for assets that have a concept of shares.
Fixed
- Started using the new fast\_info from yfinance to fetch prices. Hopefully
this should fix the temporary errors with fetching ticker prices.

Changed
- `lak` commands now don't print stack trace by default. Added a flag `--debug`
to enable printing of the stack trace.

Added
- Added functionality in `lak list lots` to optionally print account names
and terms for the tax lots.

Changed
- `lak analyze allocate' now supports asset classes with zero desired ratio.
Thanks [rapidleft](https://github.com/rapidleft).

Added
- Added functionality in the `cache` module to prefetch multiple cached objects
in parallel threads.
- Added prefetch method in assets that calls the newly added functionality
in the `cache` module. Also, added a prefetch method to portfolio that
prefetches the prices/names for all the assets in the portfolio in parallel.

Changed
- lak command that access the whole portfolio now uses prefetch to
speed up refreshing the prices of the portfolio by using multiple threads to
do so.

Added
- A new command `lak analyze allocate` which suggests how to allocate new cash,
while making sure the actual asset allocation remains close to the desired
allocation. This command can also be used to get rebalancing suggestions or to
withdraw money from the portfolio. In all cases, it will suggest changes that
will minimize the relative difference between actual asset allocation and the
desired asset allocation.
- A new
[recipes doc](https://github.com/sarvjeets/lakshmi/blob/develop/docs/recipes.md)
documenting tips and tricks for using Lakshmi.

Changed
- Changed some of the common methods to return percentages rounded to 1 digit
rather than 0.
- Earlier asset classes with no money mapped to them were not returned when
returning asset allocation. Now all asset classes are returned regardless of
whether they have money mapped or not.