clear failure message for simplify, when lock file outdated - references #394
introduce LockFile.Create method
extract same update functionality into a function
reorder parameters for better chaining
Merge pull request #403 from theimowski/master

clear failure message for simplify, when lock file outdated
Merge pull request #406 from mexx/refactorings

some refactorings
RELEASE_NOTES
RELEASE_NOTES
Bump version to 0.17.3
Merge branch 'master' into update

Conflicts:
	src/Paket.Core/LockFile.fs
	src/Paket.Core/UpdateProcess.fs