added 'defined' and 'known' functions to expression parser
tree7c38e7e468d759b9f4fbc84babeb9e7edac6ab67
-rw-r--r-- 59 .gitignore
-rw-r--r-- 36 Jamfile
-rw-r--r-- 113 Jamrules
drwxr-xr-x - gfx
drwxr-xr-x - libs
drwxr-xr-x - samples
drwxr-xr-x - src