Updated xml files from kate repo.

Added modelines.xml, now used in some of them instead of alert.
Added markdown.xml from kate repo.
Added modelines and markdown to cabal file.
Fixed bug in haskell.xml:  FilePath listed as a function!
Version bump to 0.5.5.1.
Added Markdown to list in README.
xml: forward-port Rust syntax data

Imported from official repo:
https://github.com/mozilla/rust/blob/master/src/etc/kate/rust.xml
Merge pull request #37 from adridu59/master

xml: forward-port Rust syntax data
Updates for latest syntax files from kate; added restructuredtext.
Changed lua highlighting so constants/variables highlighted as normal.
Handle restructuredtext module name in ParseSyntaxFiles.
Updated rust xml file.
Reverted alert_indent.xml, since latest didn't parse.
Added restructuredtext module to cabal file, version bump to 0.5.6.
Updated changelog.
allow blaze-html-0.7
Version bump to 0.5.6.1.
Updated changelog
Updated xml syntax definitions from kate repository.
Made regex matches respect 'case-insensitive'.

This should fix pandoc #1285.