Contexts are necessary for factories to resolve QSEN into FQSENs based
on partial namespaces and namespace aliases. These provide DocBlocks
with the namespace name and namespace aliases.
The new ContextFactory will enable third parties who don't use
phpDocumentor's Reflection component to construct a Context based on
a class reflector or namespace name (and file contents).
DocBlocks may start with #@+ and #@- to indicate that they are (the start) of a DocBlock
template or the end of a template.
In this commit I have changed the way a DocBlock is parsed to interpret this information
and added tests to show for it. In addition I have added more comments to the Regular
Expression responsible for splitting a DocBlock to show the business rules more clearly.
This is the first step in implementing https://github.com/phpDocumentor/phpDocumentor2/issues/42.