remove/ignore build artefacts, #274
changelog for v3.3
Implement Arduino's random() functions, issue #215

Also, when https://github.com/spark/core-communication-lib/pull/25
is merged, then the user will automatically have a secure random
seed after handshaking with the Spark Cloud.
unit tests + factored out random() to separate files
changelog update assuming PR #289 is merged.
include in spark_wiring.h for new random functions.
(And integration test case for that bug.)
linkies for git issues/PRs
allow apps to use c++11 features also
fixes #210
isAlpha, isUpper etc.. arduino-compatible functions, with API/smoke tests.
Created spark_wiring_constants.h for hardware-neutral wiring definitions such as HIGH, LOW and boolean.
Print class uses String so provide a forward reference in cases where the header hasn't been pulled in.

(the string header also depends upon the print header, so we can't just pull in spring_wiring_string.h since that will have no effect.)
fix for segment fault when converting values to binary. (The buffer size was set assuming a 16-bit integer, not 32-bit.)
fix for converting `INT_MIN` to string, cannot negate in that case because `-INT_MIN` isn't representable in 32-bits.
unit tests
gah..travis build couldn't find INT_MIN. strange it compiled locally. Would be great if travis allowed you to host your own docker vm, then we'd have a portable build environment, avoiding these build discrepancies.
proper fix for INT_MIN - it was in spark_wiring_string.cpp, not in the test case
increased time waiting for test case and logged current time (to be sure the script is waiting.)
need a local build env that is a mirror of travis.
moved setting gnu++11 flag to correct location
added today's PRs to change log
unwanted change.
call Spark.process() when OTA_FLASH has started, regardless of mode. Fixes #294