Add SEQUENCEP.
Add LIST, SEQUENCE to TYPECASE.
Add SEARCH and stuff.
Add SEARCH, MISMATCH testcases.
Add Tilde D: Decimal to FORMAT.
Preliminary DOCUMENTATION, APROPOS and friends.
Load documentation.lisp.
Fix FORMAT specifier X.
WARN should accept FORMAT-like arguments.
Handle unknown FORMAT specifiers for now.
Fix negative index arguments for ELT.
Add EXTERNAL-ONLY (as seen in SBCL).
Use EXTERNAL-ONLY for APROPOS and friends.