support input file on command line, other small fixes

we need to support the input file on the command line for pdb.
Expr_Greater, Expr_SmallerOrEqual, Expr_BooleanAnd, Stmt_InlineHTML

the inline HTML thing obviously is a hack but these will need to be
rewritten anyway, and this will make it easier
implement elseif support
fill out operators
don't treat lookups specially; implement switch

don't treat lookups with a special function; they're just expressions,
and there are contexts where it could be a lookup or (say) a variable
expression
support PHP's dynamic attribute lookup via getattr
unary ops, instanceof, postinc, for, continue

- unary minus and bitwise not
- translate for into while
- translate instanceof in python's instanceof()
- translate PHP `x++` into a python `x += 1` statement
isset support -- surprisingly tricky
unset support