[first cut/WIP] Left overs + cleaning up carmen-cache

[aarthykc]

Worked on cleaning carmen-cache this weekend:
We no longer use normalization-cache in carmen. Opening this PR to remove normalization cache along with simplifying carmen-cache that would involve:

• using the write to disc pattern that we used for fuzzy-phrase, so as to be able to remove duplicative code in memory.cpp and rocksdb.cpp
• (stretch goal) split NAN_METHOD() from the C++ code in order to be able to easily get C++ to talk to rust through C

cc @apendleton, @aaaandrea (since both of you have worked extensively on carmen-cache)

[apendleton]

Stale; work on this proceeded instead in #135