[TARGET_STM32F4] new structure for F407 and F429 targets -part1

move specific files from old position into new target folders under
target_stm32f4
[TARGET_STM32F4] new structure for F407 and F429 targets - part2

remove target_stm32f407vg files
[TARGET_STM32F4] new structure for F407 and F429 targets - part3

remove target_stm32f429zi files
[TARGET_STM32F4] new structure for F407 and F429 targets - part4

Solves the problem NULL -> HAL_NULL for the additional hw blocks in the
larger mcus.

For F401 and F411 this was already solved in #596.
[TARGET_XXX_L053YY] filename - includename case missmatch

Changed include filename to a lower case l from higher case L because of
Windows-Linux incompatibility. Removed temporarly taget DISCO_F407VG
from build_travis so that Travis runs trough the build process.
Merge pull request #641 from ohagendorf/master

Targets: TARGET_XXX_L053YY - filename - includename case missmatch
Merge pull request #639 from ohagendorf/bcostm_branch_f4xx_structure_reorder

Targets: Nucleo F4xx - Reorder f4xx structure
Merge pull request #640 from bcostm/master

Targets: Factorisation of NUCLEO_F302R8 and F334R8 cmsis folders
[STM32L0] Update version in files, add Cube driver release note
[STM32L0] Update registers map file
[STM32L0] Remove useless files
[NUCLEO_L053R8] Update GPIO structures

Due to latest registers map file used.