added dummy '1w convert' to avoid breaking scripts

Signed-off-by: Maximilian Güntner <maximilian.guentner@gmail.com>
Merge pull request #236 from mguentner/onewire_convert

added dummy '1w convert' to avoid breaking scripts
print slash between manufaction month and year
debug output for detection of SDHC card
removed redundant informations in debug messages
new sub-menu for storage devices
new function vfs_unlink(): removes a file
undo accidentally made change
Merge pull request #239 from eku/sdcard

Sdcard improvements
vfs_sd_unlink implementation
ECMD "rm" to delete a file on SD card
finally inlucde vfs_sd_unlink in VFS_SD_FUNCS
Merge pull request #241 from eku/vfs_unlink

Vfs unlink