* Adding Cortex-A support for gnuarmeclipse
* Preventing '-mthumb' from being added to Cortex-A builds.
Previously, both '-mthumb' and '-marm' were being supplied to the
compiler (in that order). Because '-marm' came last, the compiler
respected this option. This change makes it so '-mthumb' is added for
all 'Cortex-M' targets only.
* Renaming to capital .S for Eclipse compatibility
Add sleep/deepsleep functions to platform layer which are replacing HAL
functions with the same name, rename existing symbols in HAL layer
to hal_sleep/hal_deepsleep. This way sleep functions
are always available, even if target doesn't implement them, which makes
the code using sleep clearer. It also enables us to make decision on in
which builds (debug/release) the sleep will be enabled.