v0.5.0 -- SQL, Labels, and Community

We've spun out of the google namespace, so this is community build number one. There's some good chatter in IRC and places, and expect some notes in the mailing list soon. The project isn't dead, it was just resting.

Now that we can add contributors, it's time to tag and build a release as a baseline. There may be some turbulence as some longstanding changes get merged over the next version or two, so before we do that, here are some binaries for people to try out the latest.

Highlights:

• Postgres/SQL backend support
• Add support for LabelContext() to query the Label field across Quads
• SaveOptional()
• Many, many bugfixes

Full changelog:

barakmich: Add SaveOptional() to save predicates if they exist, and add the
dennwc: path: Added SaveOptional
dennwc: Fix interface conversion in Gremlin
barakmich: fix build on 1.6 -- more accurate interface conversion
josephschorr: Make call to `Sprintf` lazy
barakmich: query/gremlin, graph/path: Add support for querying with labels
Quentin-M: Fix NPE in SQL initialization
jzelinskie: dockerfile: fix go install command
jzelinskie: initial Dockerfile
barakmich: graph: make quadstore init functions idempotent
barakmich: Update README to mention Postgres and remove unused trello board
jzelinskie: add Triple function
Quentin-M: Fix SLOW DELETEs
Quentin-M: Fix a deadlock behavior with DELETE transactions
Quentin-M: Ensure that quads in a transaction are applied in the desired order.
Quentin-M: Use a Size() estimate for SQL Quadstore when noSizes is enabled.
barakmich: sql: Combine AND(Fixed, SQL) and fix Save() roundtrips
barakmich: graph/sql: Use an IN clause when optimizing a fixed iterator
barakmich: query/gremlin: fix building Or iterator, add test
barakmich: query/gremlin: Refactor in terms of graph/path
Quentin-M: Fix NPE in SQL Quadstore
Quentin-M: Improve Transaction: deduplicate quads, allow adding/removing a quad in the same tx
barakmich: Fix corners after causing a couple merges
ds--: Adds exporting capabilities
barakmich: Add migration tool and use protos in Bolt store
barakmich: graph: Postgres backend
sayden: Typo fix when building cayley from scratch
sayden: Order of parameters when using :a and :d are switched
Kavec: Refactor for readability
kortschak: graph/bolt: don't panic on unitialised store
barakmich: Fixes memstore transaction semantics
Quentin-M: Make the SQL connection fail-fast
Quentin-M: Fix NPEs in SQL Next and Contains
barakmich: Roll the Go version forward on Travis builds (new stable)
barakmich: Add check for multiple all iterators
kortschak: internal: move {config,db,http} into internal
skynet: Update README.md
neonstalwart: add string comparison to value comparison iterator
tmlbl: Small REPL Improvements
igm: Fixed multiplier for position of "label" in case of "po" key entry
cayleydb: Update README.md
barakmich: Docs update based on @KamiQuasi #280
lytics: Use new import path for go-uuid
jzelinskie: travis.yml: bump appengine dependency
barakmich: Add transaction (a list of deltas) as a primitive for applying sets o…
nii236: Widened visualisation box to 100%
panamafrancis: Added myself to the A+C
barakmich: Add Save and Has API functions
Quentin-M: Allow opening a database (bolt, leveldb, mongo) through Go API
barakmich: Clean up Linkage definition
allonhadaya: In out predicates
barakmich: Fix bug where first Bolt iteration ignores deletion
barakmich: Fix describe in Or iterator
neonstalwart: collapse 2 iterations into 1 in memstore
op: Fix nil pointer panic when meta bucket is missing
barakmich: Fix LevelDB deleted-triple iterator stack overflow bug
neonstalwart: move cmp to where it's used
kortschak: graph: remove redundant type
barakmich: Go API
heyalexej: update leveldb link and fix some https links in README
andrew-d: Refactor packages
andrew-d: Fix TravisCI tests
andrew-d: Remove deprecated ResultTree API
Dabaez: Update README.md
barakmich: Implement the Unique iterator