Update path (#470)

* Update path

Attempting to change directories into this path (i.e., `/home/centos/src/project_data/aws-fpga/SDAccel/examples/xilinx_2017.4/getting_started/host/helloworld_ocl`) draws an error because the `xilinx_2017.4` directory is empty, now, and `xilinx` is a symbolic link that points to the latest release (i.e., `/home/centos/src/project_data/aws-fpga/SDAccel/examples/xilinx_2019.1`).  Additionally: `helloworld_ocl` is no longer a sub-directory of `host`; it's now a sub-directory of `hello_world`: so this part of the path should be updated as well.

* Fix unset flags

The alphanumeric part of these flags (i.e., `f`) are preceded by en dashes, when they should be hyphens; as using the former instead of the later results in errors (`-bash: unset: ``–f': not a valid identifier`).

* Update path to workspace directory

This change is consistent with 48c3048, and the basename of the image, but has a different filename extension because of the transparency.

Author: Kenso Trabing

SDAccel/docs/README_GUI.md

@@ -29,7 +29,7 @@ The SDAccel examples from the github are downloaded by the above steps. However,
 
 First change directory to **helloworld_ocl** example. 
 ```
-    $ cd <git area>/SDAccel/examples/xilinx_2017.4/getting_started/host/helloworld_ocl
+    $ cd <git area>/SDAccel/examples/xilinx/getting_started/hello_world/helloworld_ocl
 ```
 The github examples use common header files and those needs to be copied in the local project source folder to make it easier to use. 
 Type the command **make local-files** to copy all necessary files in the local directory.
@@ -46,9 +46,9 @@ To debug using gdb inside from SDX gui few additional commands are needed to exe
 
 ```
    $ mv /usr/local/Modules/init init.bak
-   $ unset –f switchml
-   $ unset –f _moduleraw
-   $ unset –f module
+   $ unset -f switchml
+   $ unset -f _moduleraw
+   $ unset -f module
    $ sdx
 ```