cameo: adding toolpath adaptation language (in progress)

- README: added description of toolpath adaptation language (in progress)
- Makefile (OBJS): added lex.yy.o and y.tab.o
- Makefile (SLOPPY): relaxed compiler warnings for files generated by
  flex/yacc
- Makefile (clean): added lex/yacc intermediate files
- Makefile: added lex and yacc (bison) to build process
- Makefile: added rules for lex/yacc intermediate files
- lang.l, lang.y: toolpath adaptation language (in progress)

cameo/README

@@ -19,3 +19,62 @@ LICENSE, Version 2:
 
 For your convenience, a copy of the complete license has been included
 in the file COPYING.GPLv2.
+
+
+Toolpath adaptation language
+----------------------------
+
+Loading paths:
+
+  gerber <diameter> [<filename>]
+  gnuplot <diameter> [<filename>]
+  clear
+
+"gerber" and "gnuplot" each add paths from a file to the list of paths
+already loaded. "clear" removes all paths.
+
+If the a file name is omitted, standard input is read. The diameter is
+the default tool diameter.
+
+Note that "clear" preserves the translation set with "align", "array",
+and "translate". This way, multiple files can be processed with the same
+translation.
+
+File output:
+
+  write [<filename>]
+
+Writes all loaded paths in gnuplot format to the specified file. If the
+file name is omitted, "write" writes to standard output.
+
+Units:
+
+  mm
+  mil
+  <number>mm
+  <number>mil
+
+The words "mm" and "mil" set the input to the specified unit. The
+default unit is millimeter. If a number is followed by "mm" or "mil"
+without intervening space, the unit is overridden for this number,
+without affecting the default input unit.
+
+Note that "mm" and "mil" only affect dimensions in the command file
+and have no effect on the interpretation of toolpath files.
+
+
+Horizontal adjustments:
+
+  align <ref> <x> <y>
+  align <ref> <x0> <y0> <x1> <y1>
+  array <x-step> <y-step> <x-index> <y-index>
+  translate <X> <y>
+  reset
+
+Vertical adjustment:
+
+  z [<z0>] <z0-depth>
+  
+Tool compensation:
+
+  tool