[All] Optimize based on efficiency guide

[mocchira]

There are some rooms to optimize code based on the below links.

• http://www.erlang.org/doc/efficiency_guide/commoncaveats.html
• http://www.erlang.org/doc/efficiency_guide/listHandling.html
• http://www.erlang.org/doc/efficiency_guide/functions.html
• http://www.erlang.org/doc/efficiency_guide/tablesDatabases.html

For example,

• replace erlang:size\1 with erlang:byte_size/1 when the argument type is binary

[yosukehara]

• Need to replace erlang:size\1 with erlang:byte_size/1 as below:

* leo_dcerl/src/leo_dcerl.erl:128:  DiffSize = erlang:size(Val) - OldSize,
* leo_dcerl/src/leo_dcerl.erl:136:  [?JOURNAL_OP_CLEAN, StrKey, erlang:size(Val)]),