Implemented support for escaping triple quotes

Fixes #40
Add support for escaping closing braces
Merge pull request #40 from jroper/40-escape-triple-quotes

Support triple quotes in a template
Merge pull request #41 from jroper/escape-closing-brace

Add support for escaping closing braces
Clarify the exception thrown when template filenames have non accepted
characters in them.
Merge pull request #43 from Banno/clarify-invalid-template-name-error

Clarify the exception thrown when template filenames have non accepted characters in them.
Fix matching on scalaBinaryVersion in build.sbt

Dbuild manipulates scalaBinaryVersion which breaks twirl's matching when
selecting specs2 dependency. See typesafehub/dbuild#145 for details.
Merge pull request #44 from gkossakowski/master

Fix matching on scalaBinaryVersion in build.sbt
Workaround for dbuild's scalaBinaryVersion mishandling.

This is another workaround for typesafehub/dbuild#145. This time we deal
with the problem of Scala version-dependent inclusion of source files to
be compiled. Selection of a source folder is broken because it is based
on scalaBinaryVersion which dbuild overrides. The workaround is to
fallback to "2.11" value for scalaBinaryVersion when the one set in the
build is not included in the known set ("2.9.3, "2.10", "2.11").
Merge pull request #45 from gkossakowski/master

Workaround for dbuild's scalaBinaryVersion mishandling.
Add source url for source linking in aggregated docs
Add play documentation for template engine