Merge pull request #855 from mispencer/ReloadSolution

Expose OmniSharp's ReloadSolution command
Adding 'mail' filetype (mutt) to blacklist

Fixes #847
Bumping to newest Requests & requests-futures
Updating to Boost 1.55
Fixing Boost build with Clang 3.4

This applies the following Boost patches that have already been applied
upstream:

https://github.com/boostorg/atomic/commit/6bb71fdd8f7cc346d90fb14beb38b7297fc1ffd9.patch
https://github.com/boostorg/atomic/commit/e4bde20f2eec0a51be14533871d2123bd2ab9cf3.patch

These patches will be in Boost 1.56 but until then we need to make the local
changes.

Fixes #864
Resolving a minor lint error
Cygwin should build compiled Python modules as dll
Check for the existence of msbuild.exe as well.
Windows cmake puts the dlls in RUNTIME_OUTPUT_DIRECTORY
Explicitly disable cygwin win32 legacy mode to avoid warnings
Cygwin should not use mono
Update OmniSharpServer for cygwin path conversion
Pass client path mode to OmniSharpServer on run
Support cygwin test compilation