drivers/modem/u-blox.c and include/nuttx/drivers/u-blox.h:  Add an upper half driver for the U-Blox Modem.  From  Vladimir Komendantskiy

fs/vfs/fs_poll.c: Fix handling of sem_tickwait() return value sem_tickwait() does not return an -1+errno, it returns a negated errno value.  Noted by Freddie Chopin.

drivers/i2c: Move wrapper that implements I2C_WRITEREAD using I2C_transfer from pc9555.c to a new, comon i2c directory

drivers/sensors/mcp9844:  Driver for the MCP9844 I2C digital temperature sensor with a selectable resolution

mkdeps.sh and mkdeps.bat have been deleted.  All configurations must now use the compiler mkeps program

tools/cnvwindeps.c: Add a tool that will convert dependencies created by a Windows native toolchain for use the Cygwin make