Fixed #346: Heredoc is not respected in line number calculation. And some other fixes and specs related to heredoc.

Renames LocalDependency to PathDependency

Adds support for local dependencies in Projectfile

[Specs] Adds convenience method context

Add limit to all String#split variants

Context does the same as describe, but is more semantic on some contexts
(no pun intended).

[String] Adds size method for strings

This is something ruby supports and probaly the most used method to find
the length of a string.

RNG namespace for number generators

Random::ISAAC pseudo random number generator

Enables to select an engine for Random. The Engine may be
initialized with a seed and must respond to #next_number

Removed Random#srand and other srand methods that don't work
anymore (one may seed the Engine instead).

Added conway and wordcount to examples (based on http://arthurtw.github.io/2015/01/12/quick-comparison-nim-vs-rust.html )

Use Mersenne Twister to generate random numbers.