SWIG interface: Remove most function definitions
SWIG interface: Remove most function definitions

Now that we are automatically grabbing all the function definitions,
remove all the function definitions that don't need special handling.

This fixes several incorrect declarations (that were originally correct but
got change without updating them here).

Among the functions that got removed, these ones (in addition the ones
that got fixed in the previous commit) had incorrect declarations:
linkage_get_num_words
linkage_get_num_links
linkage_get_words
linkage_unused_word_cost
linkage_disjunct_cost
linkage_link_cost
linkage_corpus_cost
linkage_get_violation_name
All the "bool parse_option_get_(): functions (were defined as returning
int, caused extra C code to convert int to bool and also a warning on
Windows).

opencog/link-grammar,ampli/link-grammar,ampli/link-grammar,linas/link-grammar,linas/link-grammar,ampli/link-grammar,linas/link-grammar,ampli/link-grammar,ampli/link-grammar,linas/link-grammar,ampli/link-grammar,opencog/link-grammar,linas/link-grammar,opencog/link-grammar,linas/link-grammar,opencog/link-grammar,linas/link-grammar,ampli/link-grammar,linas/link-grammar,ampli/link-grammar,linas/link-grammar,opencog/link-grammar,opencog/link-grammar,opencog/link-grammar,opencog/link-grammar,opencog/link-grammar,ampli/link-grammar