change pic_find_rename API
Revert "reserve the 0 symbol for system use"

This reverts commit 816343bd31628180e5118ef8f093e61dc2f138b6.

Conflicts:
	include/picrin/value.h
	src/state.c
[refactor] analyze_define
[refactor] add analyze_declare
cleanup. move analyze_lambda
when procedual-define is analyzed, don't create a lambda expression
inside, call analyze_procedure directly instead.
get rid of redundant symbol to value cast
Merge branch 'refactor-analyzer'
add pic_list7
cleanup
record cfunc procedure names
print cfunction name in debug print
record procedure name in irep
show irep names in debug print
add pic_proc_name
Merge branch 'record-procedure-name'
call symbol_rename as much as possible
macro transformer should never return macro objects
no need to handle set!/if/begin syntaces at macroexpansion stage
cleanup