Added Arduino libraries to auto dependency search

Compiler warning option added

Some improvements

New variable EXCLUDE_DIRS which can be used to filter one or several
directories during wildcard search of header and source files.
OTA tool variables are now overridable.
Last added USB serial port is now the default for the upload.
Documentation and help updated.

Some new variables added

BUILD_EXTRA_FLAGS:
Can be used to add additional compilation options
ARDUINO_EXTRA_DESC:
Enables additional Arduino configuration fiels, e.g. extra boards.txt

The Arduino configuration files are now sorted correctly before
parsing starts

Added support for new partion build in esp32

Added new configurable parameter for c preprocessor C_PRE_PROC_FLAGS

Major update, esp32 support added

esp32 support added
help function added
Improved Arduino configuration files parsing
Added functions for listing of configuration file settings
Used SPIFFS settings is now displayed after link operation

Some new features added

Dump and restore flash memory contents
Possible to specify an alternative bootloader via variable

Bugfix

Fixed problem with build info when using a subdirectory to the
sketch directory as build root

Removed erroneous check for file system

File system generation added

It is now possible to build and upload SPIFFS file system images