Smi, Value32/64 about escargot

[ksh8281]

A. we tested large Value array typed malloc, but performance is too bad..(versus SmallValue array)
because telling to bdwgc element of array are POD or pointer is slow.
but even internal value of SmallValue is always pointer, odd internal value of SmallValue is always integer,
so we don't have to tell to bdwgc element of array is POD or pointer

B. we tested doing common operations with SmallValue. but it is slow...
testing it's type on every operation takes much time. because there is no type information(int, undefined, null, pointer-value...) saved directly(versus Value).
EDITED) I missed one point. doing many floating point operations occurs so many gc_mallloc due to saving floating number in SmallValue

C. In 32 bit system, store Value into SmallValue has 4 byte gain + preventing memory leak
in 64 bit system, store Value into SmallValue has 0 byte gain but this preventing memory leak

That's why we use Value on computing, SmallValue for storage

I am glad if you reduce Value<->SmallValue converting cost

[zherczeg]

I created common values for smi and value on 64 bit, and it is working now. Please check #92, is this what you prefer?

[ksh8281]

#92 is very cool. that is good way reducing conversion costs I think