Bias CharMatcher.precomputed() implementation towards BitSetMatcher, as per http://code.google.com/p/guava-libraries/source/detail?r=7218498c1e19a789a5064ae750db7e929e2e8287 comments
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=41247243
Complete a TODO to avoid redundant copies of entry arrays in ImmutableMap construction pathways.
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=41289454
Fix ImmutableMap.copyOf's null checking on a singleton map with a null key or value.
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=41297381
Minor bug fix and simplifications in common.collect, including:

* Iterables.skip(iterable, size)'s iterator would wrongly remove the last element of the input if the user called [next(), remove()].
* In Iterators.concat, instead of using checkNotNull and Arrays.asList, just use ImmutableList.of
* Use Itera{tors,bles}.addAll instead of for loops in Sets factory methods
* Simplify Lists.charactersOf implementations
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=41300544
Hide deprecated FluentIterable.toImmutable* methods internally.
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=41302220
Merge remote-tracking branch 'google/master'