A side-effect of changing serial settings via TERMIOS (such as tcsetattr) is that serial interrupts were being left disabled.  This is not a problem if the serial configuration is changed when there are no open references to the serial device.  In that case, serial interrupts are disabled and will not be enabled enabled until the serial device is first opened.  But it is fatal if the serial device is already opened and if there is a task waiting to receive data.  In that case, the side-effect of disabling interrupts is fatal:  That task is then left hanging with interrupts disabled.

Implements CONFIG_TIME_EXTENDED as we discussed relative to providing the last 3 members of the tm struct and support for filling them in and even using the wday in the STM32 RTC. From David Sidrane.

Add conditional logic so that people who use F1 don't have to be bother with meaningless RTC MAGIC settings

drawline/drawLine should not take a boolean to select non lines caps or capping at both ends.  drawline/drawLine also needs to be able to put a line cap on one one end of a line

Implement line caps by drawing a file circle at the each endpoint of a line with a radius equal to half of the width of the line

Add a 'capped' boolean parameter to all drawline/drawLine functions/methods.  The idea is that this will produce better joining between lines

SAMV7:  Apparently the data sheet is wrong, SDRAM clocking must be enabled at the PMC or the SDRAM does not work!  The data sheet says that there is no clock control for SDRAMC