mptp 0.2.3

Changes

• Replaced hsearch() which was causing an (innocent) error message on OSX with custom hashtable
• Corrected file name in error messages when failing to open files

Notes

1. The pre-compiled linux binary mptp-0.2.3-linux-x86_64.tar.gz is compiled statically with libgsl support.
2. The file mptp-src-0.2.3.tar.gz contains the mPTP source code and does not require autotools installed.
3. Files v0.2.3.tar.gz and v0.2.3.zip are generated by GitHub, and require autotools installed (as when cloning the repository).