fix(mod/lock): Use dedicated channel to shutdown goroutine properly

If closeChan is available and stopWatchChan was closed by defer
select selects a single channel randomly. This causes a panic sending to closed
channel.
fix(mod/lock): Use CreatedIndex in the first node to watch

ModifiedIndex in the lock directory is not incremented and the event
store has only 1000 histories for now.

Acquiring a lock is not queued while (index - ModifiedIndex) > 1000 and
prevIndex exists.
fix(v2): Use case-insensitive check on bool query params

Fix issue #261
doc(api): Document prevNode
Merge pull request #545 from bcwaldon/doc-prevNode

doc(api): Document prevNode
fix(dashboard): disable some tab indexes.
Merge pull request #544 from bcwaldon/case-insensitive-query-params

fix(v2): Use case-insensitive check on bool query params
Merge pull request #546 from sym3tri/dashboard-tabindexes

fix(dashboard): disable some tab indexes.
bump(mod/dashboard): rebuild the dashboard for the latest fixes
fix(scripts/build-release): use cross compilation
doc(CHANGELOG): document v0.3.0
Merge pull request #548 from philips/0.3.0

doc(CHANGELOG): document v0.3.0
bump(README): increase the version of the README to 0.3.0
fix(README): move contact closer to contributing
Change token example to use returned value only

The discovery.etcd.io/new already returns a complete URL containing the host, so there is no need to specify it on the command line.
doc(CompareAndDelete): Add missing CAD docs

Fixes issue #549
doc(CompareAndSwap): clarify prevIndex in CAS
chore(gofmt): gofmt compare_and_delete_command.go
Merge pull request #550 from badboy/patch-1

Change token example to use returned value only
feat(scripts): use zip for windows and darwin

zip files are more common on OSX and windows. Use those file formats for
those two platforms.