Notify caller of sync/spawn command errors
riak_core_metadata:to_list/1,2

these are convenience functions for debugging and testing, although
probably not so useful for production code
close metadata fold iterators upon termination

as of 0b59e4cd30ffedd29cea592f2edb347f41095019, iterators must be
closed when they are no longer used.

addresses #450
option to prevent writes of resolved values on metadata read

a new option, {allow_put, boolean()} can be passed to get/3,
iterator/2, fold/4, or to_list/2. the default is to perform the write.

addresses #440
increase broadcast's initial eager set size for larger clusters

increasing the fanout reduces the chance of requiring exchange to deliver
messages to all alive nodes during a broadcast. This patch decreases the
likelyhood by 20 to 30 percent, on average.

The chosen fanout is determined by the discrete function
`round(log(NumNodes)+1)`, where `log(x)` is the natural log and `NumNodes`
is the number of nodes in the cluster.  For practical cluster sizes,
this curve has a maximum fanout of about six peers, dependning on what
is considered the upper limit of practical cluster sizes.

addresses #438
enable read/write_concurrency on cluster metadata ets tables

addresses #443
Add get dot and dot type for dvv style causality

Conflicts:
	src/vclock.erl
Changing how pathing is determined:
* Adding new property to riak_core.app.src called platform_data_dir
* Removed ring_state_dir from riak_core.app.src
* Adding function to riak_core_ring_manager named ring_dir() to build a path for the ring file using either platform_data_dir or ring_state_dir
Changing path to prevent double ring directories.
Adding the ring dir to platform_data_dir
Make get_entry return more information for callers

Add test for get_entry
Add valid_entry function to test if a dot is a valid format
Merge pull request #467 from basho/pevm-status-safety

Bound the time that stats calculation can take
Export hashtree:flush_buffer/1
Enable bloom filters for AAE LevelDB instances
add staleness tagging for a couple of different conditions
Peer reviewed schema changes
Address review comments
Updated unit tests for schema
Address review comments (fix docs, harden vdor validation fun)
Add a specific function for determining if a clock descends a dot