Fix embarassing search bug

This commit fixes a very embarassing search bug that caused some
searches to return false positive results for data in the buffer.
While iterating through Limbo to find search matches, we were not
ensuring that the key of the write matched the key of the search
request which meant that we would return any write that had a value
matching the query regardless of what the key was. This commit fixes
that issue.
improve error message for easier debugging
Fix whitespace Text deserialization

This fix changes the deserialization logic for Text (and everything else)
such that we do not trim the resutling string that is deserialized from
the byte buffer. This fix is needed so that we can correctly handled cases
when the user stores data with leading or trailing whitespaces.

Hopefully this fix does not break anything else. In previous testing, it
seemed like it was necessary to trim strings on deserialization to prevent
flakiness, so we'll need to be on the lookout as to whether we should revert
this commit.