Converted preproc logic to library and moved some utility stuff to lwlib The strbuf and strpool stuff is generally useful so move it to lwlib where other such things live. Also, package the preprocessor logic into a library for easy use in multiple places.

\.exe$
\.o$
\.d$
\.a$
~$
\.orig$
/lwbasic$
/lwlink$
/lwobjdump$
/lwar$
/lwasm$
/lwcc$
/lwcc-cpp$