Added a new validate class, AlphanumericExt, that allows a few extra characters ontop of regular Alphanumeric validation. Closes #17 (#25)

Implement log levels for pkg tlog

Allows a version/branch string to be parsed in download url

Skips a file if after the execution of the template, it only contains
whitespace characters

Fixes #10

- Allows using specifiers for trimming preceding/trailing whitespaces in
  templates.

Fixes #9

Fixes #5