Assume default versions for each language

[clue]

Travis does not require an explicit definition of the version to test against, whereas JoliCi does. I noticed this in one of my projects, the following .travis.yml should reproduce this:

language: php

PHP Notice:  Undefined index: php in phar:///usr/local/bin/jolici/src/Joli/JoliCi/BuildStrategy/TravisCiBuildStrategy.php on line 271
PHP Warning:  Invalid argument supplied for foreach() in phar:///usr/local/bin/jolici/src/Joli/JoliCi/BuildStrategy/TravisCiBuildStrategy.
php on line 273
PHP Catchable fatal error:  Argument 2 passed to Joli\JoliCi\Matrix::setDimension() must be of the type array, null given, called in phar:
///usr/local/bin/jolici/src/Joli/JoliCi/BuildStrategy/TravisCiBuildStrategy.php on line 303 and defined in phar:///usr/local/bin/jolici/sr
c/Joli/JoliCi/Matrix.php on line 26

Supporting this should be fairly straight forward, we just need to define a list of default versions for each language and fall back to this list if no other version is defined in the TravisCiBuildStrategy.

[joelwurtz]

Will be fixed in the next release thanks again for the report.