tango-dark.conf: caret is now red. (Improves readabilty)
Tweak tango-dark.conf a bit

* Set the caret colour to a bright yellow (You Like?)
* Make the "brace good" and "brace bad" colours a little nicer
Update tango-dark.png screenshot
Add new color theme "Black Scheme"
Create some notes about adding a new theme to the project

In the file ADDING-A-THEME.md.
Create some notes about releasing Geany-Themes as a package
Add DELETEME file temporarily to test infrastructure hooks
Add some notes about adding and distrbuting schemes to README.md
Remove temporary DELETEME file while testing infrastructure hooks
Add DELETEME file temporarily to test infrastructure hooks
Remove test file
Improve machine API to the themes

* Improve index/index.json
* Add MD5 sum of that file into index/index.json.md5
* Remove experimental index.conf and index.xml files from the build
* Remove genindex script and related template files
* Add screenshot-missing.png icon to screenshots dir
  - From elementary-xfce icon theme (status/64/image-missing.png)
* Update index/README.md detailing the format/fields of the JSON file.
Change THEMES_VERSION to match next Geany version

* Remove naive/stupid version mismatch tests on Geany version
* Reformat indentation a bit in Makefile
Add `make help` to Makefile with a little bit of info
Add simple `install.sh` script

In case someone is too lazy to copy manually and also to lazy to
install and use GNU Make.
Switch version number scheme used in themes

From now on the version field in color scheme files is a simple
integer incremented each time the scheme is changed. To avoid
arbitrarily re-setting all versions to 0 (or some other number), I
just removed the decimal point from the existing versions so they
still have some significance.

* Update mkindex.py to handle new format
* Remove deleted note from index/README.md
* Update index/index.json and MD5 sum of it
Add automatic version bumping script

Makefile default rule now calls `autobump` and `index` targets. To
use this, call `make` after changing any of the colour schemes.

The way it works is versions.log contains the md5 sums of the
color scheme files. The autobump script checks the old sum from
versions.log against the current color scheme file and if any of
them changed, it opens the color scheme and increments the version
number in it and then stores the newly computed sum (after the bump)
back into versions.log. When the `index` rule is run in the Makefile,
it updates the `index.json` and `index.json.md5` files based on the
changes.
Update comment in color schemes about version bumping

This is also a good way to test/demo the new script :)
Add experimental field to list supported Geany versions

This can be used by a colour scheme manager or by the user directly
to see which Geany versions the scheme is compatible with.
Add "screen_hash" field and rename "md5hash" to "scheme_hash"

These are the fields containing an MD5 sum of the screenshot and
color scheme files in the index.