Update README.md

Clarify the scons requirement.
Improve graphite sink to avoid "invalid line received from client".

The invalid line issue is that graphite sink is constantly sending to the graphite server the string "\n", even when it has not received any metrics and as a consequence it makes carbon give out errors.
Merge pull request #31 from pasku/master

Improve graphite sink to avoid "invalid line received from client".
Add a simple makefile
Adding support for delta updates to gauges
Testing delta updates to gauages
Update the readme
Updating changelog. Thanks to @pasku
Read UDP packets until error, then return to event loop
Update the changelog
Update README.md with more gauge delta info.
Merge pull request #34 from aleasoluciones/master

Update README.md with more gauge delta info.
Added statsite.spec and "clean", "sdist", and "rpms" rules in Makefile.
Merge pull request #36 from veetow/master

Added statsite.spec and "clean", "sdist", and "rpms" rules in Makefile.
Packaging 'sinks', which I overlooked initially.
Merge pull request #38 from veetow/master

Packaging 'sinks', which I overlooked initially.
Adding 'parse_stdin' bool flag
Optionally disable TCP and UDP listeners
Support stdin as a client
Adding integ tests for stdin