Twig 2.7+ support

Refactored all Twig namespaces to use the 2.7+ standard in preparation of release of 3.0.
Removed some old deprecated Twig class references.

Clear compiler on each template

v3.0.2

Added a parent call to the compiler so it is cleared for each new nod…

Fixed several issues with Twig functions

Fixed remaining getLine to getTemplateLine renames. (#7)

Cleaned up tests and git ignore.

Twig 2.0+ and PHP 7.1+

Add support for Twig 2.0+ (#6)

* #99 fixing MacroCompiler, when context did not contain current arguments
* updating plovr location
* update travis and bumped php version from 5.3 to 5.4
* updated twig/twig@2
* update travis to 7.0, 7.1
* Update to the latest version of PHPUnit.

Merge upstream changes

Merge latest changes from schmittjoh repository (#5)

Fixes #107 for twig up to v1.30.0
* Add composer flag: prefer-stable: true
* Libraries should not include a composer.lock file
* Relax twig version requirements
* Update composer.json

Change twig dep to ^1.25 rather than ^1.24
* ignore composer.lock

Update Twig 1.25+ test expressions

• Optional arguments in all Twig test expressions are now supported.

Fix for older versions of Twig

• Added Travis CI test for the lowest versions possible.
• Refactored node checks.
• Updated minimum version for Twig.

Support for Twig 1.25 and higher

• Updated deprecated calls to getNode.
• Updated Travis tests.
• Updated composer requirements.