These limits seems to be picked arbitrary, and I just made it arbitrary larger.
We need to reconsider these limits, ideally providing to user a way to customize the limits.
FWIW, When the last time I've tried to run gcc's torture testsuite with wasmi it also bumped into this limit.
Fixes#41.
* Initial implementation
* Not use grow as it is makes debug builds very slow
* Use Pages::BYTE_SIZE for LINEAR_MEMORY_PAGE_SIZE
* Tidy docs.
* Use memory_units from git.
Sergey Pepyakin
Nikolay Volf