TRQ-2509: Properly handle basic shell syntax in qsub script

- properly (as shell does) handle quotations in qsub script #PBS
  arguments in make_argv()
- fixed wrong static buffer operations in do_dir()
- fixed and re-enabled qsub_functions() unit tests
- wrote make_argv() unit test
Merge pull request #256 from DSRCompany/TRQ-2509_wrong_qsub_script_quotation_parse

TRQ-2509: Properly handle basic shell syntax in qsub script