Implement configurable metric namespace.

This is an implementation of pull request etsy/statsd/#137.
(optionally) change process name of children

settings the process title to a human readable name helps
to identify which subprocess is doing what. besides looking nice
it also helps to give a better inside in what parts of bucky are
using resources when looking at the output of ps, top and alikes.
remove log.debug statemens from udpserver when not running in debug mode and use arguments for string formatting on log functions

the log.debug statements are taking up a significant part of execution time (as measured by cProfile) this patch makes it so that these statement are only loaded when debug mode is True.

Changing all places (where possible) which call logger functions in combination with string formatting to use arguments on the logger function instead of doing the string formatting in place. This is a (micro-)optimalisation when the message will not be logged
fix typo in cfg.debug name
optimalisation by removing duplicate float() conversion

for these divisions we are sure that one side of the equation is already a
floating point number.

benchmark shows this can double performance for the division:

In [20]: %timeit 123/1.2
10000000 loops, best of 3: 77.1 ns per loop

In [21]: %timeit float(123)/1.2
10000000 loops, best of 3: 189 ns per loop
remove variable assignment for variable which is only used once (micro optimalisation)
revert fields[0] is a string
add wrapper to start bucky from source tree
set nice levels, drop priviledges and add supervisord example config
add requirements
use requirements in setup
fix multiple parameters in the same line, microoptimize line handling code for speed
optimalisation; if not "|" in sample seems to be about 16% faster then len(fields) < 2
simplify guage delta code
rename bucky to bucky2
fix missing self reference for metrics
fix all style problems indicated by flake8 bucky2 --ignore=W391,E501
fix style problems for non package files
add .travis.yml
add note about origin project in README