Concatenate expr command arguments before evaluating.
Add support for logical OR and AND with shortcircuit evaluation.
Don't include the "expr" command as part of the string to parse.
expr: Add support for conditional statements x?y:z
expr: Support eq, ne, lt, le, gt, ge for string comparisons.
expr: Fix case where ParseExprDisjunct and ParseExprConjunct would panic an array index error.
expr: fix the length strs is initialized with, suggested by @strickyak.
Merge pull request #6 from MrWerewolf/expr

Expr