Load non-namespaced functions only if previously unloaded

[padraic]

Checks if one of the more unique functions is previously defined. If not, will try to load all of the functions. This should help with hamcrest loading cross-project boundaries. Won't check all functions so clashes can still occur with non-hamcrest code (which is likely okay to leave alone).

[aik099]

The Hamcrest.php file is generated. Please instead:

1. add return statement to the generator/parts/assertThat.txt file (when function assertThat exit then don't do the rest)
2. run php generator/run.php
3. what's changed goes to PR

I advise to use Hamcrest\Matchers static class instead of global functions.

[cordoval]

ping @aik099 is this still needed? if yes it needs a rebase

[aik099]

This is no longer needed after #22.