Optimize stack for Arduino.

Optimize stack for Arduino.

In RI, headeroptions are maintained as array with default size as this macro.
A default 100 headeroptions are too high and results in a structure size of 3KB+.
Moreover any vendor will not add 100 CoAP options.
Also optimized few clonings.

Change-Id: I65860c44ec1ba0c3ef2800a88f27ecad0f483568
Signed-off-by: Abhishek Sharma <ce.abhishek@samsung.com>
Signed-off-by: Veeraj Khokale <veeraj.sk@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/10585
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Ashok Babu Channa <ashok.channa@samsung.com>