added lazy tag initilization / binding.
fixed bug with single inetrgal type tag lookup
added contains and iter to mesh
stability improvement to mesh length
Merge pull request #172 from scopatz/tags

Super Awesome Tags For To Blow Your Mind
minor repr string update for mesh
added pre-load functioanlity to data source, transmue.chainsolve now 200x faster.
made using temperature as part of the data source key optional.
rm'd temp flag from NullDataSource
more flags for not using temperature on data sources
partway through chainsolve decay refactor when a bug in fundemendal data was found.
ensdf reader update to grab approximate rates
reverted change.  This needs more thought.
more tansmute meanderings
fixed up docs to use new breathe
Updated MCNP homepage URL.
Merge pull request #174 from cbrachem/staging

Updated MCNP homepage URL.
Merge pull request #173 from scopatz/enquicken

added pre-load functioanlity to data source, transmue.chainsolve now 200x faster
Merge branch 'staging' of github.com:pyne/pyne into staging
Couldn't figure out @gonuke's des=0.0 trick in 2 hrs.  This'll have to wait for v0.4