TurboJPEG: Thread-safe error message retrieval
Introduce a new C API function (tjGetErrorStr2()) that can be used to
retrieve compression/decompression/transform error messages in a
thread-safe (i.e. instance-specific) manner. Retrieving error messages
from global functions is still thread-unsafe.
Addresses a concern expressed in #151.
diff --git a/doc/html/structtjregion.html b/doc/html/structtjregion.html
index af2a473..36c0afa 100644
--- a/doc/html/structtjregion.html
+++ b/doc/html/structtjregion.html
@@ -24,7 +24,7 @@
<tr style="height: 56px;">
<td style="padding-left: 0.5em;">
<div id="projectname">TurboJPEG
-  <span id="projectnumber">1.5</span>
+  <span id="projectnumber">1.6</span>
</div>
</td>
</tr>