Add OpArray class

This adds an OpArray class that replaces the previous opLines array. It is
part of the larger effort to make the compiler more PHP like. We will need
to store some more data during compilation (for CVs etc), which needs a
separate structure.
Enable error reporting

In the last commit I fixed a few warnings that have been causing a lot of
test failures for me. Now make sure that everybody sees the same errors :)
Add back support for default values

Also add method for getting the zval from a constant expression. This
is needed for other types of initializers as well.
Refactor quite a bit...
Merge branch 'master' of https://github.com/ircmaxell/PHPPHP
More work completely breaking things. Trying to refactor zvals to use proper copy-on-write
Clean up static implementation
Add test-results markdown generation
Fix HTML encoding issue on html test results
Update README.md

Add links to test results and test suite
Add support for casting
Merge branch 'master' of https://github.com/ircmaxell/PHPPHP
Use offset jumps instead of object jumps

Jumps really shouldn't be O(n)... Also gets rid of many NoOps.
Fixed continue
Merge pull request #7 from arnaud-lb/continue-fix

Fixed continue
Add output buffering
Add support for list, fix array implementation, add array functions
Add support for iterating by reference, Add a few array functions
Objects support
Merge in object support, Closing PR#8, minor code cleanup