Renames IsSetBefore into IsSetWithin, to follow comments from https://github.com/tpierrain/NFluent/issues/107
Merge branch 'master' of https://github.com/dupdob/NFluent into integrateCyrille
Updates the release note to include Cyrille's bug fix.

Improves the UserReportedIssuesTests.SpuriousExceptionOnError() test by indicating the Expected error message.
Fixes Cyrille's pull request StyleCop issues (including usage of tabs instead of spaces).
Makes TimeUnit as mandatory parameter for EventWaitHandle checks.
Introduces a Duration.ConvertToMilliseconds static method.
Moves duration checks into the new Duration tests fixture, and replaces previous NUnit Assertions with Checks for it.
Updates the backlog file.
Adds IsNaN() check for double and creates T4 that is cloning double for float.
Updates T4 so that the FloatFloatingPointBinaryRelatedTests file is properly generated.
Adds the IsFinite() check. ( https://github.com/tpierrain/NFluent/issues/110 )
Fixes the release note.
Sets the proper PCL value within the nuspec and the ReleaseNote files.
Resets version number and release note (after yesterday release of 1.2).
Adds the AsyncRelatedTests fixture with a single test illustrating https://github.com/tpierrain/NFluent/issues/112 (ignored for the moment)

Migrates NFluent from .NET 4.0 to .NET 4.5 to prepare the compliance with Async/Await concept.
Introduces comments to exclude MS tests integration stuff from NCrunch coverage (see within ExceptionHelper type) which restores test coverage to 100%.
Temporary fixes a NCrunch issue with conditional compilation symbols (here: dotNet45) : http://forum.ncrunch.net/yaf_postst935_Issue-when-using-conditional-compilation-symbols-in-linked-file.aspx
Workarounds a NCrunch issue when using conditional compilation symbols (http://forum.ncrunch.net/yaf_postst935_Issue-when-using-conditional-compilation-symbols-in-linked-file.aspx) by forcing the DOTNET_45 symbol for all possible configurations of NFluent.40 and NFluent.40.Tests projects.

The issue was that none of the code or test depending on this conditional compilation symbol was taken into account by NCrunch.

Note: that one was painful to troubleshoot and to fix.
Renames NFluent.40.* folders to NFluent.45.*
Updates build script to be able to target .NET 4.5 instead of .NET 4.0.
First and naive implementation of Check.ThatAsyncCode() + tests (still failing so far).