Don't encode the same argument over and  over.
update a few tests
forgot version bump. v0.1.8
This fixes Issue #42 and puts in at least one regression test for 64-bit
integer values, which work in node.js up to about 2^54 and down to
-2^54. May as well make a best effort to get them right.  This issue is
due to a regression introduced in commits  6b4c80c and 0b4f361, which
taken together always encode larger integers as doubles, even when
they shouldn't be.
A few more regression tests can't hurt...
I got tired for someone to fix this.  I'll make my own
version bump