rename -b|--build to -b|--buildid [auto_flash_from_PVT.sh]
fixed the logic of target url replacing of command mode [auto_flash_from_PVT.sh]
modified the inconsistent parameter name of ENV_VAR and .ldap file
[auto_flash_from_PVT.sh]
updated gitignore
modified the usage message [auto_flash_from_PVT.sh]

also removed .ldap from repo
Updated README.md
Updated the usage message of flash tools
Disable GUI for MAC now. Issue #20 will add GUI for MAC.
Fixed typo
Added nexus4 support for TWCI flash tool
Added file check for shallow_flash and flash_TWCI
Added error handle of download desktop client
Refactoring the auto_flash_from_TWCI
Modified flash "-help" description
Added new pvt flash tool
Updated naming rule for pvt
Refactoring auto_flash_from_PVT.sh
Updated the dialog layout of flash_pvt
Let auto_flash_from_PVT.sh work now
Updated usage message