better cli-rework

[tDwtp]

I did have an open pull request #374 (after discussion I propably close it).

TL;DR:

• add a general header for cli and differ between LIB/API
• orderd options and execute (all of) them in order. proper arguments for scripts too.

I would like to refine my approach a little. I really like your argument to just ship a single file. In general I would like to embed a gravity.h file into gravity which can be exposed with --header. It would contain all definitions necessary (I am working on it). I would need to make some functions available too and hide others. This is where I would like to differ between GRAVITY_API and GRAVITY_LIB. LIB is for using gravity from a dll/so to embed somewhere. API is to expose to native libraries/modules loaded via imports.

Now in a seperate move I would also like to make the cli a little bit more ... common? Currently, any option gets ignored unless its the last (with its parameter). And your executing file is at the end and not after the last option. however most interpreter do not work like this. I would like to change that as well as execute all of the -i options, automatically detect serialized files to make -x obsolete and let -c be a seperate execution mode. (where -o would be obsolete). This is already partially done and a pull request ill follow soon.

Side question: Would you mind having a specialized binary format for compiled code (not [just] JSON)? I would like it to be as expandable as JSON. A simple TLV encoding might already do the trick.