* Lot of fixups and code cleanups

* Fix tree structure (some nodes was lost)
* Add endch extra information on each node
* Use parse as default action

* Remove unnecesary force flag in parse_pushword ()
* Fix a bug while parsing null strings and empty words

* Minor syntax and warning fixups

* Some code simplification (-34 LOC)
* Added 't/relang' as a draft specification for it

* Do reads on filedescriptors using blocks of 1024 bytes
- 4-5 times faster
- Use memory pools to allocate N nodes in a shot
- Faster, cleaner and easily freedable
- Implement and use alt_tree_free()
* Added node type 'operator'.
- Show node type in tree walk (alt -t)
* Added some syntax tests in t/hello.alt

* Fix parser with comments and ops
- Added new chars to be handled as ops !~<>
- Multiline comments are now handled as operators
- Extended t/ops.alt test file

* Correctly parse and identify the 'operator' words
- Fixes the use of =, += , ... expressions without spaces
- Added test file: t/op.alt
* Added locdiff in makefile

* Identify each tree node with a type of word
word, string, integer, float, operator?
* Debug is now optional and configurable in runtime
* Added flags to main() (-p parse, -t trace, else run)
* New syntax for variables '$', functions are now not starting with '.'
- Update hello.alt example

* Added script.c that executes the ast tree generated by tree.c
* Move some stuff from tree.c to alt.h
* Extend the basic t/hello.alt