feature: Add large files recommended for benchmarking by Brenton

I've added these files to this repository, as Git LFS entries.

fixup: Clarify comment in .gitattributes

Author: ConnorGray

.lfsconfig

@@ -0,0 +1,4 @@
+[lfs]
+	# Ensure that a default checkout of this repository doesn't download any
+	# large files.
+	fetchexclude = *

README.md

@@ -102,3 +102,27 @@ Out[2]= $Failed
 This means that CodeParser was built with a newer version of Wolfram System than your system supports.
 
 To fix this, build CodeParser from source with the version of Wolfram System that you will use.
+
+## Benchmarks
+
+> Some of the benchmarks test large data files. Those files are tracked in this
+> repository to ensure that benchmarks are always run against identical input.
+> [Git LFS](https://git-lfs.github.com/) is used to ensure that a basic checkout
+> of this repository remains small, which is important in CI/CD builds.
+
+To run the benchmarks, first ensure that the large benchmark files have been
+checked out locally using:
+
+```shell
+$ git lfs pull --exclude="" --include="*"
+```
+
+This will override the default settings in [`.lfsconfig`](./.lfsconfig).
+
+## File Overview
+
+* [Tests/files/large/](./Tests/files/large/) contains files
+  managed by [`Git LFS`](https://git-lfs.github.com/). The files in this
+  directory are used by the benchmarks. These files should never be modified, to
+  ensure that benchmark comparisions between different revisions of this
+  repository can be meaningfully compared.

Tests/files/.gitattributes

@@ -0,0 +1,2 @@
+# Use Git LFS to store all of the files in the files/large/ directory
+large/* filter=lfs diff=lfs merge=lfs -text

Tests/files/large/ReliefPlot.nb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:08dbac51a17a741b997bd7c60d13ea0fe7d6c970191aa2c07356f2c26d70b1b1
+size 244135221

Tests/files/large/expandedCompanyDataNew1.m

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:c32e17edc64ee9b94e6c7a36c9dd7e837a1be0d965c51098ae41edd428874af8
+size 71487044

Tests/files/large/geomagneticmodels.m

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:682f7198f2468d2ebfa23eacb971dce688cc3229873feb4960f704bf823eec92
+size 6827153