Organize examples and API documentation - supplement to !430
This supplement to !430, both intended to replace bulky !421.
1. Fixed broken links
2. Added links to available examples in API documentation, where missing
3. Updated links to point directly to example folder (to show README.md with example description)
4. Added README.md in docs folder info to point reader to ReadTheDocs instead of doc sources, ref. https://github.com/espressif/esp-idf/issues/243
5. Fixed some typo errors / Sphinx warnings
6. Fixed memory leak in example, ref. https://github.com/espressif/esp-idf/issues/209
See merge request !440
The following issues mentioned during MR!341 review were fixed:
1) Core dump test application description
2) Usage of CONFIG_ESP32_ENABLE_COREDUMP_TO_FLASH and CONFIG_ESP32_ENABLE_COREDUMP_TO_UART
3) FLASH_GUARD_START macro usage is fixed in flash API
4) Core dump module logging facility
5) cache util functions doc updated
6) interactive delay before print core dump to uart
7) core dump partion support in build system
2. update example comments and other minor changes
3. rename API: i2c_cmd_link_create/i2c_cmd_link_delete (+4 squashed commits)
Squashed commits:
[2e0ac3e] 1. coding style: add one space after condition key words.
2. modify i2c.h, use gpio_num_t instead of int, improve comments of return values
3. add i2c index in index.rst
4. add readme for i2c example
[4991d92] update i2c.doc
[88b672e] driver: i2c
1. add mux and spin lock to run in a thread-safe way.
2. modify example code
[4eb15fe] driver: i2c code
1. add i2c master code
2. add i2c slave code
3. add i2c example code
4. add DRAM_ATTR for I2C array
1. add sigma-delta code and example.
2. add gpio output signal in io matrix.
Squashed commits:
[a25e7d4] minor changes for doc
[6a03a1e] minor changes on comments and doc.
[97dd9e4] Add doc.
update index.rst
change example index
1. TW8657, WIFI send the whole packet to smartconfig;
2. modify API annotation of smartconfig and sniffer;
3. export smartconfig APIs to programming guide;
