UpdateAssemblyInfo: create local tmp file in \obj.

Now UpdateAssemblyInfo task creates temp assembly info file within
$(ProjectDir)\obj\$(ConfigurationName).

Fix #146.
Added new test scenario showing issue in #296
Removed ShortVersion and ShortVersionParser. It limits flexibility when switching to GitVersion
Fixed libgit2 bug/deprecated

In libgit2 the "Credentials" property is deprecated, instead
CredentialsHelper should be used. In 0.19 there is a bug with the
Credentials property when cloning, using the "correct" way
(CredentialsHelper) fixes the bug:
libgit2/libgit2sharp#834

In order to be consistent I changed also the fetch method.
Merge pull request #317 from unic/fixCredentials

Fixed libgit2 bug/deprecated
Merge pull request #308 from JakeGinnivan/BetterSwitchingToGitFlowStory

Better switching to git flow story
Upgrade fody
Merge pull request #318 from JakeGinnivan/FodyUpgrade

Upgrade fody
Merge pull request #316 from inTagger/feature/fix146

UpdateAssemblyInfo: create local tmp file in \obj.
Added 'GitVersion init' command which creates a sample GitVersionConfig.yaml file
Support older configuration files, warn user but upgrade file
Switched NextVersion.txt to GitVersionConfig.yaml
Merge pull request #320 from JakeGinnivan/GitVersionInit

Added 'GitVersion init' command which creates a sample GitVersionConfig....