API improvement and bugfixes

API changes for improved generality.

• added ovf_file_initialize and ovf_segment_create to API. This enables either defaulting the values of an object or creating a new one (which includes the initialization), enabling better C++ wrapping
• changed integer definitions of OVF formats
• also some minor aesthetic changes

Bugfixes

• Fixed reading binary data containing line breaks
• fixed "appending" to a nonexistent file, which should now correctly create the file
• Due to the nature of binary data, it may randomly contain line breaks. It is now parsed until the "End: Data" statement is encountered
• other minor things

Bugfix for `found` and `is_ovf`

The C struct contained ints instead of bools, which is now fixed. This removes a bug in the Python bindings, which would not correctly show if a file's is_ovf was true.

Rewritten parser for better stability and performance

• significantly improved adherence to the OVF 2.0 specifications

• improved the description of the specifications in the Readme

• using the PEGTL for parsing to improve predictability, stability , performance, etc.

• binary is now ensured to be written as little endian IEEE standard floating point

• binary is always read with the assumption of little endian IEEE standard floating point

• corrected some misinterpreted keywords

• added better error messages for missing keywords

• irregular meshtype is now functioning

• capitalisation is now ignored correctly

• some bugfixes in the Fortran bindings

• empty lines, comment lines and empty lines containing a comment are now correctly ignored

Bugfixes and improved segment initialisation

• Segments can now be initialised by function call in Fortran and C
• Segments are now automatically initialised on construction in Python
• Fixed some possible segmentation faults in bindings
• Also made Filter_File_Handle header only
• Also updated fmtlib

Added Fortran bindings

• fixed a bunch of small bugs
• improved library structure
• minor changes to ovf_segment and ovf_file
• added Fortran bindings, included in CMake by default

Initial release of basic, working API

A lot of cases may still crash, but a few basic tests are already running.

This is the initial design of the API, which may therefore change a lot in coming releases!