Remove references to CONFIG_SYSLOG in nshlib

apps/system/hex2bin:  Move the portable library portion of hex2bin to nuttx/libc/hex2bin where it can be shared with the OS internals.

Add platform files for Olimex STM32 E407

Basic CAN utility library

apps/platform/Kconfig:  Fix an inclusion error.  Was including /platform/mikroe-stm32f4/Kconfig.  Should include through the symbolic link /platform/board/Kconfig

apps/canutils/libcanard: update version

Remove lowsyslog().  The new syslog() includes all of the functionality of lowsyslog().  No longer any need for two interfaces.

apps/examples:  Change some *err() message to *info() messages if what was a *dbg() message does not indicate and error condition.

apps/graphics and netutils:  Change some *err() message to *info() messages if what was a *dbg() message does not indicate and error condition.

apps/nshlib:  Change some *err() message to *info() messages if what was a *dbg() message does not indicate and error condition.

apps/platform:  Change some *err() message to *info() messages if what was a *dbg() message does not indicate and error condition.