add tests for strict (32-bit) int
implement strict (32-bit) int operations in jsemitter
s/_(Post|Pre)fixExpressionEmitter/_(Post|Pre)IncrementExpressionEmitter/g, to match the names of the expressions
add failing test (local var should be defined in case of postinc of int in static var decl.)
define temp vars in the lazy initor if necessary (fixes t/run/367)
add failing test (re fold-const vs. strict 32-bit int)
the result of const-folding may differ bet. number / int
update bootstrap compiler so that the change in prev. commit takes effect
do not emit unnecessary "| 0" for bitops
regen bootstrap compiler (so that the prev. commit takes effect)
clarify the reasoning behind the returned types of binary ops
add a failing test-case (const-int % 0 should be folded to NaN)
[bugfix] int % 0 should be const-folded to NaN (instead of to zero), as clarified by a test-case in the prev commit
add a test case to clarify that a numeric literal in source should never be handled as ```int```
add failing test
```-int``` should return a number
Merge branch 'master' into kazuho/experiments/32bit-int
Merge branch 'master' into kazuho/experiments/32bit-int

Conflicts:
	tool/bootstrap-compiler.js
rebuild bootstrap compiler
Merge branch 'kazuho/experiments/32bit-int' (closes #294)