add influxdb handler

this file add support to influxdb
removed graphite references
corrected bad batch_size typo
append typo
removed reference to schema

schema variable is replaced by a BOOL named 'ssl' (True or False) to reflect to python influxdb ssl management.
added proper import check
influxdb import error
more corrections regarding version check
renamed file to prevent colision
added header info
added time_precision

time_precision is used in influxdb to define the precision.
For now, diamond only log with a definition of seconds... keep using defaults
changed doc
max_backlog_multiplier typo
removed the trim
corrected batch count

batch count was badly calculated on metrics name instead of number of points to record
Merge pull request #623 from prune998/master

add influxdb handler