feat(server): add net/http/pprof endpoints

Add some basic profiling endpoints over http to start digging into
memory and request latencies.
feat(store/store_bench_test.go) add a benchmark for set operation of store pkg
We randomly generage N 3 level keys. We benchmark the speed of setting each key into etcd store.
add a setWithJson test
feat(etcdbench): Add -endpoint flag to etcdbench
fix(etcdbench): Check for error in etcdbench set operation
Merge pull request #482 from bcwaldon/etcdbench

etcdbench -endpoint flag; error reporting
add mem stats for sets benchmark
Merge pull request #479 from philips/add-debug-endpoint

add-debug-endpoint
fix(Documentation/profiling): note about using the right binary
fix(scripts/test-cluster): use v2 flags and find the path for etcd
bump(github.com/coreos/go-log): 70d039bee4b0e389e5be560491d8291708506f59
Merge pull request #486 from philips/document-profiling-binary

fix(Documentation/profiling): note about using the right binary
feat(store_bench) add set bench for different value sizes
add delete bench
feat(docs): modify for sync to CoreOS website
fix(docs): remove header
Merge pull request #488 from robszumski/master

feat(docs): Prepare to sync security doc to CoreOS website
fix(bench): remove trailing slash

Remove trailing slash. This works around
https://github.com/coreos/go-etcd/issues/82
feat(metrics): Add github.com/rcrowley/go-metrics
- Fix typo.