update doc
	modified:   INSTALL-windows.txt
Don't put mext dir on file_search paths globally,
rather only while doing require.
moved dont kill list. but should make zero difference
	modified:   pw/pw.mac
moved stuff around, but makes little difference
	modified:   tpsolve/tpsolve.mac
	modified:   tpsolve/tpsolve.system
Fixed bug
removed dontkill of symbols %and, %or,
left dont kill "%and" "%or".
this solves reloading problems
	modified:   tpsolve/dontkill.mac
format
	modified:   pw/pw.mac
update usage docs.
	modified:   INSTALL-windows.txt
	modified:   README
	new file:   USAGE
	new file:   README.build
	new file:   buildall_gcl_win32.mac
add os_type_symbol()
	modified:   mext_defmfun1/mext_defmfun1_code.lisp
	modified:   mext_system/mext-maxima-system.lisp
disable test that fails on gcl 2.6.7
	modified:   tpsolve/rtests/rtest_to_poly_solve.mac
edit doc
remove blank
	modified:   testall1.mac
fix bug:
 mext_info(pack), returns nothing if
 mext_list() has not been called.
	modified:   mext_system/mext-maxima-system.lisp
add url field to mxt info
	modified:   mext_system/mext-maxima-system.lisp
	modified:   pw/pw.mxt
add url
	modified:   discrete/discrete.mxt
test implicit
	modified:   implicit/implicit.system
	modified:   implicit/implicit_code.mac
	modified:   implicit/rtests/rtest_implicit.mac
	modified:   rtest_renumber.pl
renumber
	modified:   tpsolve/rtests/rtest_to_poly_solve.mac
	modified:   .gitignore
	new file:   bin/trylines.sh
Move shell and perl to ./bin