Check that object names can be unmangled
gsub with useBytes = FALSE is very slow

* can't see this being a problem for object names that are going to be
  written to the filesystem anyway.
Formatting
Treat 'status' as possible vector
Merge remote-tracking branch 'jefferis/mangle' into rds2

* jefferis/mangle:
  gsub with useBytes = FALSE is very slow
  Check that object names can be unmangled
Export RDS2 class
Merge remote-tracking branch 'jefferis/rds2-fast' into rds2

* jefferis/rds2-fast:
  a few more notes in TODO about performance
  faster objectFile
  add optimised dbExists method for RDS2
  don't forget to load filehash in todo sample code
  fix bug in paths when initialising with existing RDS2 db
  Add notes to TODO re optimisation
  Much faster serializing with compression and xdr off
Merge branch 'rds2' of github.com:rdpeng/filehash into rds2

* 'rds2' of github.com:rdpeng/filehash:
  Export RDS2 class
  Treat 'status' as possible vector
  Formatting
  gsub with useBytes = FALSE is very slow
  Check that object names can be unmangled