README small change
Merge branch 'master' of github.com:EarlGray/language-snippets
Merge branch 'master' of github.com:EarlGray/language-snippets
fp/secd: read commands and stdin from different sources
fp/secd: LEQ, misc

0) added LEQ (less or equal opcode) for ATOM_INT
1) SUB and caddr are compilable
2) tail recusrion is #ifdef'ed
3) global env is printed as `*global_env*` to avoid cycles in expressions like (display symbol?)
4) improved control debug messages
5) removed experimental APT opcode