Improve README

README.md

@@ -0,0 +1,30 @@
+Intel® Instrumentation and Tracing Technology (ITT) and Just-In-Time (JIT) API
+==================================================================================
+
+This ITT/JIT open source profiling API includes:
+
+  - Instrumentation and Tracing Technology(ITT) API
+  - Just-In-Time(JIT) Profiling API
+
+The Instrumentation and Tracing Technology (ITT) API enables your application
+to generate and control the collection of trace data during its execution 
+across different Intel tools.
+
+ITT API consists of two parts: a _static part_ and a _dynamic part_. The
+_dynamic part_ is specific for a tool and distributed only with a particular
+tool. The _static part_ is a common part shared between tools. Currently, the
+static part of ITT API is distributed as a static library and released under
+a BSD/GPLv2 dual license with every tool supporting ITT API.
+
+### Build
+
+To build the library:
+ - On Windows, Linux and OSX: requires [cmake](https://cmake.org) to be set in `PATH`
+ - Run `python buildall.py`
+ - Windows: requires Visual Studio installed or requires [Ninja](https://github.com/ninja-build/ninja/releases) to be set in `PATH`
+
+### Run
+
+To load the library:
+ - On Windows and Linux: Set environment variable `INTEL_LIBITTNOTIFY32`/`INTEL_LIBITTNOTIFY64` to the full path pointing to `libittnotify[32/64].[lib/a]`
+ - On OSX: Set environment variable `DYLD_INSERT_LIBRARIES` to the full path to `libittnotify.dylib`