Adding event package for pluggable global event listeners.
queryservice: Fix & improvements to comments parser.

The comments parser had a bug where it would fail to
detect comments like this: /** ... */. This CL fixes it.
I've also the panic scheme of handling failures.
The resulting code is longer, but more readable.
I've also written more tests to cover the corner cases.
Move test utility function to _test.go file.
Merge branch 'event'
Adding syslogger plugin for event package.
Merge branch 'master' into vtocc
queryservice: expvars SpotCheck* -> RowcacheSpotCheck*
sqltypes: remove compiler bug workaround