Added requirements page

docs/devs/building/requirements.md

@@ -0,0 +1,15 @@
+Build requirements
+==================
+
+In general, for building i2pd you need several things:
+
+* compiler with c++11 support (for example: gcc >= 4.7, clang)
+* boost >= 1.49
+* openssl library
+* zlib library (openssl already depends on it)
+
+Optional tools:
+
+* cmake >= 2.8 (or 3.3+ if you want to use precompiled headers on windows)
+* miniupnp library (for upnp support)
+* [websocketpp](https://github.com/zaphoyd/websocketpp/) (for websocket ui)

docs/user-guide/install.md

@@ -4,7 +4,7 @@ Installing
 Building from source
 --------------------
 
-See developer section documentation for how to build i2pd from source on your OS.
+See [developer section documentation](../devs/building/requirements.md) for how to build i2pd from source on your OS.
 
 
 Windows, Android, Mac OS X  

mkdocs.yml

@@ -22,7 +22,7 @@ pages:
     - Filesharing: tutorials/filesharing.md
     - Using RetroShare with i2pd: tutorials/retroshare.md  
 - Developer Section:
-    - Building from source: 
+    - Building from source: devs/building/requirements.md
         - Unix: devs/building/unix.md
         - Windows: devs/building/windows.md
         - Android: devs/building/android.md