Accumulate read data in string instead of array.

The array version uses a lot of memory.
Merge pull request #85 from mrjameshamilton/patch-1

Accumulate read data in string instead of array.
VERSION = 3.0.2 (3.0.1 was tagged with this set to 3.0.0).
Merge branch 'master' of github.com:pda/pheanstalk