foreach instruction in the parser
Instructions as plain text and test for nested instrutions

Singli line instructions that do not start on a new line are considered as plain text.
Adds also some tests to check that nested instruction are detected correctly
Compile instruction

Generate compiled code for template instruction. This also refactors the compiler's test structure
Gists from github

This commit contains a small change to adapt to the new format returned by the code generator, but most important it fetches gists from a github user (non configurable)