Ugly-patch-oriented impl. of eval capability

- Using unix pipes to call py-compiler to compile function text
- mmc_fun.xpp used to load compiler's result of CompiledFunction
- CompiledFunction with env_table indicating names and ep indexes

Minor improvements and bugfixes

- Adding support for 'thisContext'
- Fixed mm_list_index_of comparing the same values
- Added String.==
- Added a Process:do_send with args
- Fixed (apparently) order of arguments in emit_push_closure