Added AssignVersion function to Args module.
Added AssignVersion function to Versioning module.
Included Assign function as a pattern in match expression.
Included '-a' command in usage description.
Included two test cases that have been previously deleted by replacing '-a' with another, currently anonymous, letter.
Added more parameterized test cases to make the implementation even more robust for the Devil's Advocate technique.
Renamed a function.
Added more parameterized test cases to make the implementation even more robust for the Devil's Advocate technique.
Removed a redundant function.
Moved ProjectToBuild property to .config file,

because the location of solution files may vary.
Incremented minor version,

in order to indicate that the addition of an 'assign' operation is a new
feature. This resolves #16
(https://github.com/ploeh/ZeroToNine/issues/16).
extract duplicated code into UpdateVersionsInFile function
Documented the 'assign' operation.
Enabled Visual Studio 2013 use.
Allow assignment operation to assign a new value to a version part of an existing version whilst retaining the values of the other version parts
Updated function signature of AssignVersionPart and renamed associated function in Versioning module to match.

Added documentation for assign version part operation
Updated readme 

add a separation between the -a usages for clarity
Partial Active Pattern to match AssignRank discriminated union value
Restrict integer to be greater than or equal to 0
Incremented minor version,

in order to indicate that the addition of a function to assign a
particular value to a version part is a new feature. This resolves #19
(https://github.com/ploeh/ZeroToNine/issues/19).