Add SDK 1.5.2.

http://bbs.espressif.com/viewtopic.php?f=46&t=1702

"""
Release Notes
Resolved Issues(Bugs below are eligible for Bug Bounty Program):

    Strange os_timer_arm behavior.

Optimization:

    Added SDIO slave driver. Developers are now able to implement AT commands based on SDIO interface by themselves.
    Optimized SSL shakehand.
    Upgraded second-level boot to support HSPI flash.
    Added AirKiss library.
    Updated sample code smart_config (esp_iot_sdk\examples\smart_config).
    The 114th byte of esp_init_data_default.bin is modified to be 1. Please use the latest esp_init_data_default.bin.
    Added sample code at_espconn (esp_iot_sdk\examples\at_espconn), showing how to transmit AT commands via the internet.

Added APIs:

    SDIO slave APIs
    sdio_slave_init: initialize SDIO slave
    sdio_load_data: upload data to SDIO buffer.
    sdio_register_recv_cb: register Callbacks of data received by SDIO.
    AirKiss APIs
    airkiss_version: get version information of AirKiss.
    airkiss_lan_recv: used to detect and analyze AirKiss data packets.
    airkiss_lan_pack: used to analyze AirKiss data packets, and to organize response packets waiting to be responded.
    AT UART simulation APIs
    at_fake_uart_enable : enable AT UART simulation.
    at_fake_uart_rx : AT UART RX for simulation.

Known Issue:

    SSL misbehavior.
"""

Makefile

@@ -22,6 +22,8 @@ UNZIP = unzip -q -o
 VENDOR_SDK_ZIP = $(VENDOR_SDK_ZIP_$(VENDOR_SDK))
 VENDOR_SDK_DIR = $(VENDOR_SDK_DIR_$(VENDOR_SDK))
 
+VENDOR_SDK_ZIP_1.5.2 = ESP8266_NONOS_SDK_V1.5.2_16_01_29.zip
+VENDOR_SDK_DIR_1.5.2 = esp_iot_sdk_v1.5.2
 VENDOR_SDK_ZIP_1.5.1 = ESP8266_NONOS_SDK_V1.5.1_16_01_08.zip
 VENDOR_SDK_DIR_1.5.1 = esp_iot_sdk_v1.5.1
 VENDOR_SDK_ZIP_1.5.0 = esp_iot_sdk_v1.5.0_15_11_27.zip
@@ -161,6 +163,12 @@ $(VENDOR_SDK_DIR)/.dir: $(VENDOR_SDK_ZIP)
 
 sdk_patch: .sdk_patch_$(VENDOR_SDK)
 
+.sdk_patch_1.5.2:
+	echo -e "#undef ESP_SDK_VERSION\n#define ESP_SDK_VERSION 010502" >>$(VENDOR_SDK_DIR)/include/esp_sdk_ver.h
+	$(PATCH) -d $(VENDOR_SDK_DIR) -p1 < c_types-c99.patch
+	cd $(VENDOR_SDK_DIR)/lib; mkdir -p tmp; cd tmp; ar x ../libcrypto.a; cd ..; ar rs libwpa.a tmp/*.o
+	@touch $@
+
 .sdk_patch_1.5.1:
 	echo -e "#undef ESP_SDK_VERSION\n#define ESP_SDK_VERSION 010501" >>$(VENDOR_SDK_DIR)/include/esp_sdk_ver.h
 	$(PATCH) -d $(VENDOR_SDK_DIR) -p1 < c_types-c99.patch
@@ -271,6 +279,8 @@ sdk_patch: .sdk_patch_$(VENDOR_SDK)
 empty_user_rf_pre_init.o: empty_user_rf_pre_init.c $(TOOLCHAIN)/bin/xtensa-lx106-elf-gcc
 	$(TOOLCHAIN)/bin/xtensa-lx106-elf-gcc -O2 -c $<
 
+ESP8266_NONOS_SDK_V1.5.2_16_01_29.zip:
+	wget --content-disposition "http://bbs.espressif.com/download/file.php?id=1079"
 ESP8266_NONOS_SDK_V1.5.1_16_01_08.zip:
 	wget --content-disposition "http://bbs.espressif.com/download/file.php?id=1046"
 esp_iot_sdk_v1.5.0_15_11_27.zip: