Improved install instructions

INSTALL.md

@@ -53,8 +53,14 @@ Prerequisites (LSL with bundled Boost)
     - C++ compiler (tested: XCode 8.3?)
 
 Optional / required for some apps:
-- Boost (+path set with -DBOOST_ROOT=path/to/boost)
-- Qt (+path set)
+- Boost (+path set with `-DBOOST_ROOT=path/to/boost`)
+    - to compile it yourself (in case you didn't download a precompiled version or use a different compiler) download [zlib](https://zlib.net/zlib-1.2.11.tar.xz) and extract it to the boost dir
+    - open the `x64 native command prompt for VS2015`
+    - `cd C:/path/to/boost_1_xy`
+    - `bootstrap.bat`
+    - `b2 -sZLIB_SOURCE="C:/path/to/zlib" -j8 address-model=64 --stagedir=./stage/x64 variant=debug,release link=static,shared --build-dir=build --with-chrono --with-date_time --with-filesystem --with-iostreams --with-regex --with-serialization --with-system --with-thread stage`
+    - if everything goes smoothly you should now have the libraries in `stage/x64/lib`
+- Qt (+path set with `-DQt5_DIR=C:/path_to/Qt/5.9.1/msvc2015_64/lib/cmake/Qt5/` or `set PATH=C:\Qt\5.9.1\msvc2015_64;%PATH%`)
 
 To build LSL, call either `lslbuild.py` from a valid build environment (e.g. the Visual C++ command line) or do it manually:
 
@@ -107,7 +113,10 @@ This will create a distribution tree similar to this:
             ├── libboost-system-msvc14-mt.dll
             └── [more boost]
 
-On Unix systems (Linux+OS X) the executable's library path is changed to include ../LSL/lib/ and ./lib/ so common libraries (Qt, Boost) can be distributed in a single library directory wheras specific libraries can be put in a subdirectory of the App dir. On Windows, a .bat-file is autogenerated that adds these library paths to the PATH variable and starts the program.
+On Unix systems (Linux+OS X) the executable's library path is changed to include
+`../LSL/lib/` and the executable folder (`./`) so common libraries (Qt, Boost)
+can be distributed in a single library directory or put in the same folder.
+On Windows, the library is copied to (and search in) the executable folder.
 
 If you want to build against the compiled liblsl, please see `OutOfTreeTest/CMakeLists.txt` for an example.