Correct error messages and restore validation of trace packets
Fix logic in error checking around the trace file version and minimum compatible version
* More work still needs to be done related to file compatibility, but this is a very small start
UI: Initial support for a VertexAttribExplorer
* Index buffers can be visualized as GL_UNSIGNED_BYTE, GL_UNSIGNED_SHORT, and GL_UNSIGNED_INT.
* Attribute values are parsed based on the parameters supplied in the glVertexAttrib*Pointer() call.
* The basic attribute data types are currently supported, but GL_HALF_FLOAT, GL_FIXED, GL_INT_2_10_10_10_REV, GL_UNSIGNED_INT_2_10_10_10_REV, and GL_UNSIGNED_INT_10F_11F_11F_REV are not.
* Attribute values flagged as normalized will be printed in the appropriate [0,1], [-1,1] range.
* Per-instance attributes are NOT correctly handled as of yet.
* More control of index offset and # of elements to display is coming soon.
UI: Update BufferExplorer to print float and doubles with %g instead of %e so that the shortest display format will be used, instead of always printing with exponent notation.
Merge branch 'master' of https://github.com/ValveSoftware/vogl
UI: Restore support for displaying GL_ELEMENT_ARRAY_BUFFER_BINDING as part of the VertexArray Object state.