Improved performance logging

Improved performance logging

Seperated performance logging into 2 environment variables.
Plus added a new one for controlling the frequency of logging statistics

Before one environment variable would do multiple un-related things.

--DALI_LOG_PERFORMANCE_STATS--

A bitmask to control which DALi performance statstics are logged out.

The bitmask provided is
  LOG_EVERYTHING        ///< Bit 0 (1), log all statistics to the DALi log
  LOG_UPDATE_RENDER     ///< Bit 1 (2), log update and render statistics to the DALi log
  LOG_EVENT_PROCESS     ///< Bit 2 (4), log event task statistics to the DALi log
  LOG_CUSTOM_MARKERS    ///< Bit 3 (8), log custom marker statistics to the DALi log

Example output of running:  DALI_LOG_PERFORMANCE_STATS=1 dali-demo
with a custom PerformanceLogger for dali-demo TableView Initialize()

INFO: DALI: Update, min 0.20 ms, max 2.47 ms, total (0.1 secs), avg 0.54 ms, std dev 0.25 ms
INFO: DALI: Render, min 0.06 ms, max 19.10 ms, total (0.1 secs), avg 0.94 ms, std dev 1.86 ms
INFO: DALI: Event, min 0.01 ms, max 9.38 ms, total (0.0 secs), avg 0.66 ms, std dev 2.02 ms
INFO: DALI: DaliTableView, min 81.11 ms, max 81.11 ms, total (0.1 secs), avg 81.11 ms, std dev 0.00 ms

--DALI_LOG_PERFORMANCE_STATS_FREQ--
Used to control the frequency of DALI_LOG_PERFORMANCE_STATS, e.g.
to log the statistics out every 5 seconds:

DALI_LOG_PERFORMANCE_STATS_FREQ=5 DALI_LOG_PERFORMANCE_STATS=1 dali-demo

--DALI_PERFORMANCE_TIMESTAMP_OUTPUT--

A bitmask to enable logging of time stamped events.

  OUTPUT_DALI_LOG            ///< Bit 1 (1), log markers to DALi log
  OUTPUT_KERNEL_TRACE        ///< Bit 2 (2), log makers to kernel trace
  OUTPUT_SYSTEM_TRACE        ///< Bit 3 (4), log markers to system trace ( currently not supported)

Example output of: DALI_PERFORMANCE_TIMESTAMP_OUTPUT=1 dali-demo

INFO: DALI: 966735.553251 (seconds), V_SYNC
INFO: DALI: 966735.553279 (seconds), UPDATE_START
INFO: DALI: 966735.553872 (seconds), UPDATE_END
INFO: DALI: 966735.553890 (seconds), RENDER_START
INFO: DALI: 966735.553933 (seconds), PROCESS_EVENT_START
INFO: DALI: 966735.554011 (seconds), PROCESS_EVENT_END
INFO: DALI: 966735.567137 (seconds), RENDER_END
INFO: DALI: 966735.570027 (seconds), V_SYNC

Change-Id: I392e9d3312111ce2d037e91b821996f43b4b842c