Various refactoring and bug fixes for quasiquotes

Fixes following bugs:
* SI-6871: quasiquotes should be able to handle Iterables
* SI-6877: deconstruction of type quasiqoutes doesn't work

Refactoring:
* Refactors all quasiquotes code into a single cake
* Remove parens around ctor calls
* Rename ctx into c in quasiquotes implementation
* Decreases code and commments duplication
* Adds additional default liftables
* Intern all the names used in quasiquotes
* Removes casts that are not needed any more
* Spelling and typos
* Adds more tests
* Fixes imperfect random trees generators which caused some tests to fail
Merge pull request #23 from densh/topic/quasiquotes-fixes

A number of fixes to quasiquotes