Avoid extra quotes where not strictly necessary.

Allow disabling timestamp in non-tty output.

It's not necessary to enclose in quotes every single string value
in log2met format; when using basic words, it's possible to not
quote it (as heroku does for its own logging). This keeps the
logs easier on the human eye.

This is useful if the output is already being piped to a logger
daemon that will prefix the timestamp by itself (eg: on heroku).

Add links to a loggly.com hook

Fix JSON formatter prefixing old msg/time/level fields

Update README.md - changed conflicting imports

documentation fix

Added sentry hook

Conflicts:
	hooks/papertrail/papertrail.go

syslog: let syslog output lookup level directly in Entry struct

Log level has moved from `entry.Data["level"]` to `entry.Level`. Use
that to get the right level.

Fix: #82

add GetLevel support

Signed-off-by: Doug Davis <dug@us.ibm.com>

Panic with entry instead of entry string

as the reader is not seekable and without this the panic string is
always empty 🙀

fix bug in example in README

hooks: lock on the logger before printing to stderr, printf args