Merge pull request #24 from melezov/master

Database version check now uses regex matching.
Improved Maven and Scala detection on Windows.

Since on Windows they are actually bat files, search for mvn.bat and scalac.bat in path.
Used Java File constants for special system chars.

TODO: on compilation error, check for newer library version and offer to download and retry
Minor changes.

Making IDE happy and simplifying URL change.
File locking issue fixes.

Closing used streams, delete folder retrying.
WPF support. More retrying.

Added WPF GUI support into compilation.
More retrying on some places.
It seems WPF requires full path to it's assemblies ;(
Since WPF doesn't work on Mono anyway, restricted due to path lookup.
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