1. code like `char msg[] = "xxxxxx"` unnecessarily copied the string to stack, changed to `const char* msg = "xxxxxx"`.
2. the 2rd argument of `setErrMsg` is changed from `char*` to `const char*`.
3. the 3rd argument of `setErrMsg` is removed as `strncpy` stops copying at the end of source string.

Updated nodejs connector to 1.1.1

Implemented higher level API to make it more modular
Using promises and callbacks
Argument binding is now available e.g query(select ? from ?).bind("*", "table")

Added local documentation and updated README

fix #174

Update docs within files, better naming, and added some async functionality

- Using _ to indicate variable/function is private and shouldn't be accessed
- Added JSDocs syntax to generate documentation
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Added node.js connector and example usage of node.js

Update tsched.c

fix buffer overflow and memory leak.