revised lexer configuration using SciTE property files and Textadept's terminal color definitions

 * lexer config is now in separate file installed into the package data dir,
   so it can be excluded from the teco.ini template.
 * teco.ini is generated so it can load an installed lexer.tes as ED hook
   (can still be dropped into the user's home and will work immediately)
moved manpage to doc/ subdir

later there will be much more documentation
moved redundant code related to bootstrapping and teco-driven substitutions into automake include (bootstrap.am)