Fixed issue with spaced in user directory paths causing problems because they were not quoted properly.

First reported here : https://forum.sparkfun.com/viewtopic.php?f=164&t=50231
Fixes issue sparkfun#19

Author: EmbeddedMan

platform.txt

@@ -43,10 +43,10 @@ ap3core.ambiq_sdk.path={ap3core.path}/am_sdk_ap3
 
 ## Core Includes
 includes.extra=
-includes.ambiq_sdk=-I{ap3core.ambiq_sdk.path}/mcu/apollo3 -I{ap3core.ambiq_sdk.path}/mcu/apollo3/hal -I{ap3core.ambiq_sdk.path}/mcu/apollo3/regs -I{ap3core.ambiq_sdk.path}/utils
-includes.cmsis=-I{ap3core.ambiq_sdk.path}/CMSIS/AmbiqMicro/Include -I{ap3core.ambiq_sdk.path}/CMSIS/ARM/Include
-includes.core=-I{ap3core.path}/ard_sup -I{ap3core.path}/ard_sup/ard_supers {includes}
-includes.variant={build.includes}
+includes.ambiq_sdk="-I{ap3core.ambiq_sdk.path}/mcu/apollo3" "-I{ap3core.ambiq_sdk.path}/mcu/apollo3/hal" "-I{ap3core.ambiq_sdk.path}/mcu/apollo3/regs" "-I{ap3core.ambiq_sdk.path}/utils"
+includes.cmsis="-I{ap3core.ambiq_sdk.path}/CMSIS/AmbiqMicro/Include" "-I{ap3core.ambiq_sdk.path}/CMSIS/ARM/Include"
+includes.core="-I{ap3core.path}/ard_sup" "-I{ap3core.path}/ard_sup/ard_supers" {includes}
+includes.variant="{build.includes}"
 
 
 ## Precompiled Libraries